title: Improved synthesis of mono- and disubstituted 2-halonicotinonitriles from alkylidene malononitriles.
abstract: Pyridines with 2,3,4 and/or 5 substitution remain challenging to prepare. Existing strategies to form multisubstituted 2-halonicotinonitriles via enamines suffer from dimerization of the starting alkylidene malononitriles resulting in low yields. Through alteration of reaction conditions, a new high yielding method into enamines was realized by condensing DMF-DMA and alkylidene malononitriles in the presence of substoichiometric acetic anhydride. Cyclization of the resulting enamines under Pinner conditions provided 2-halonicotinonitriles in high overall yields.
authors.affiliation: Department of Chemistry and Biochemistry, Florida State University , Tallahassee, Florida 32306, United States , and Department of Chemistry, Department of Chemical and Life Science Engineering, Virginia Commonwealth University , Richmond, Virginia 23284, United States.
authors.forename: Ashley R
authors.initials: AR
authors.lastname: Longstreet
authors.forename: Brian S
authors.initials: BS
authors.lastname: Campbell
authors.forename: B Frank
authors.initials: BF
authors.lastname: Gupton
authors.forename: D Tyler
authors.initials: DT
authors.lastname: McQuade
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D015394:Molecular Structure; D009539:Nicotinic Acids / Q000138:chemical synthesis* / Q000737:chemistry; D009570:Nitriles / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D000475:Alkenes; D009539:Nicotinic Acids; D009570:Nitriles